\name{tidem.vuf}

\alias{tidem.vuf}

\title{Do ephemeris calculations for tidem}

\description{Do ephemeris calculations for tidem.}

\usage{tidem.vuf(t, j, lat=NULL)}

\arguments{
  \item{t}{time in \code{POSIXct} format.  (It is
    \strong{very} important to use \code{tz="GMT"} in constructing
    \code{t}.)}
  \item{j}{indices of tidal constituents to use}
  \item{lat}{latitude (if missing, something is done for that)}
}

\details{Based directly on \code{t_vuf}, from the \code{T_TIDE} package.}

\value{A \code{\link[base]{data.frame}} containing
  \item{\code{astro}}{(fill in later)}
  \item{\code{ader}}{(fill in later)}
}

\examples{
tidem.vuf(as.POSIXct("2008-01-22 18:50:24"), 43, 45.0)
}

\seealso{\code{\link{tidem}}, which uses this.}

\author{Dan Kelley, based directly on \code{t_vuf} from the \code{T_TIDE} package.}

\keyword{misc}

\concept{tide}
